Potential Energy Surfaces and Stability of O in Elemental and Compound Semiconductors

1992 ◽  
Vol 242 ◽  
Author(s):  
S. K. Estreicher ◽  
M. A. Roberson ◽  
C. H. Chu ◽  
J. Solinsky
Keyword(s):  
Potential Energy ◽  
Electronic Structures ◽  
Relative Stability ◽  
Potential Energy Surfaces ◽  
Compound Semiconductors ◽  
Energy Surfaces

ABSTRACTPotential energy surfaces and electronic structures of interstial oxygen (Oi) in cubic C, Si, AIP, SiC, and BN have been calculated. The equilibrium site is a bent-bridged bond. In compound semiconductors, Oi has a larger degree of bonding with the most electronegative of the host atoms (P, C, or N) than with the least electronegative one. In addition to the barrier for rotation of O, about the < 111 > axis, which does not involve breaking a bond, we calculated the barriers for migration between adjacent bond-centered sites. There are two such barriers in compound semiconductors. In order to estimate the relative stability of Oi in the various hosts, we calculated the energies involved in inserting O2 into the lattice and dissociating it into two isolated Oi's.

Modélisation classique de champs de forces d’interactions additives dans les agrégats de type X+ Arn, (X = Li et K); mécanisme de croissance

2008 ◽  
Vol 86 (7) ◽  
pp. 911-918 ◽  
Author(s):  
F Ben Salem ◽  
F Taarit ◽  
M Ben El Hadj Rhouma ◽  
Z Ben Lakhdar
Keyword(s):  
Monte Carlo ◽  
Mass Spectrum ◽  
Potential Energy ◽  
Relative Stability ◽  
Potential Energy Surfaces ◽  
Point Of View ◽  
Magic Numbers ◽  
Energy Surfaces ◽  
Structural Point ◽  
Good Agreement

The structure and stability of the Li+Arn and K+Arn clusters are studied using pair additive potentials adapted to reproduce the ab initio calculations that we estimate as the most accurate for the Li+Ar, K+Ar, and Ar–Ar dimers. The exploration of the potential energy surfaces of the Li+Arn and K+Arn systems was carried out with Wales’ method, which includes Monte-Carlo and deformation methods. From a structural point of view, one identifies a construction mechanism in very good agreement with the interpretation of the mass spectrum done by Velegrakis, including a difference for the n = 10 case. The study of the relative stability of these structures yields magic numbers for n = 8, 10, 14, 16, 18, 20, 22, 30, 32, and 34, which are in good agreement with the experiment. [Journal translation]

Resolving the Quadruple Bonding Conundrum in C2 Using Insights Derived from Excited State Potential Energy Surfaces: A Molecular Orbital Perspective

2019 ◽  
Author(s):  
Ishita Bhattacharjee ◽  
Debashree Ghosh ◽  
Ankan Paul
Keyword(s):  
Excited State ◽  
Potential Energy ◽  
Molecular Orbital ◽  
High Spin ◽  
Potential Energy Surfaces ◽  
Valence Bond ◽  
Deep Minimum ◽  
State Potential ◽  
Energy Surfaces ◽  
Mo Theory

The question of quadruple bonding in C<sub>2</sub> has emerged as a hot button issue, with opinions sharply divided between the practitioners of Valence Bond (VB) and Molecular Orbital (MO) theory. Here, we have systematically studied the Potential Energy Curves (PECs) of low lying high spin sigma states of C<sub>2</sub>, N<sub>2</sub> and Be<sub>2</sub> and HC≡CH using several MO based techniques such as CASSCF, RASSCF and MRCI. The analyses of the PECs for the<sup> 2S+1</sup>Σ<sub>g/u</sub> (with 2S+1=1,3,5,7,9) states of C<sub>2</sub> and comparisons with those of relevant dimers and the respective wavefunctions were conducted. We contend that unlike in the case of N<sub>2</sub> and HC≡CH, the presence of a deep minimum in the <sup>7</sup>Σ state of C<sub>2</sub> and CN<sup>+</sup> suggest a latent quadruple bonding nature in these two dimers. Hence, we have struck a reconciliatory note between the MO and VB approaches. The evidence provided by us can be experimentally verified, thus providing the window so that the narrative can move beyond theoretical conjectures.

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